The deaths of three men while apparently defending their businesses from looters in Birmingham are the most tragic manifestation so far of the descent of Britain’s cities into lawlessness. In a truly appalling week for this country, the one redeeming feature has been the readiness of people from all backgrounds to protect and clean up their neighbourhoods – evidence of abiding and much-needed community spirit.

Since it is by no means clear that the crisis has played itself out, David Cameron is right to focus on restoring peace to the streets. The Prime Minister is to be commended for getting a grip when matters threatened to get out of hand. He was right, too, in Downing Street yesterday to praise the bravery of the police. While some of the choices they have made are questionable, the individual courage of officers in the most trying of circumstances cannot be gainsaid.

Mr Cameron also struck a fundamentally different note from his now famous – and somewhat naive – “hug-a-hoodie” speech. “For too long there (has) been a lack of focus on the complete lack of respect shown by these groups of thugs… there are pockets of our society that are not just broken but frankly sick,” he said yesterday.

In the Commons today, the Prime Minister needs, in the words of his predecessor John Major, to understand a little less and condemn a little more. Of course there are deeper issues at play that the Government and its successors will need to address, such as family breakdown, educational failure, welfare abuse and rampant criminality on sink estates. But they will have to wait for now.

Mr Cameron faces a more immediate question about the extent to which spending cuts will impair the ability of the police to enforce the law and protect private property. When the current disturbances have died down, a serious problem will remain in our atomised inner cities.

Boris Johnson, the London mayor, wants the Government to reconsider its planned reduction in police budgets. However, the real debate should not be about resources but about deploying the available officers better. That means putting more police on the streets on a routine basis, and not just in an emergency.

The police, in line with the rest of the public services, have become inefficient, bureaucratic and wasteful – lower budgets should not mean fewer officers. A change in policing culture is just one of the challenges that Mr Cameron needs to confront in the months and years ahead.

The Coalition has embarked on serious welfare and education reforms that are essential if the lot of the rootless youngsters who have been in the vanguard of the looting is to be improved. Moreover, plans for more lenient sentences put forward by Kenneth Clarke, the Justice Secretary, now look more misguided than ever: it must be made abundantly clear to those committing crime that there is a penalty to be paid.

There is an economic challenge, too, given the damage inflicted in the past few days on property, businesses and Britain’s reputation overseas. And there is a public expectation, reflected by Mr Cameron yesterday, that what he called “phoney human rights concerns” should not stand in the way of upholding the law of the land.

Indeed, this has been a week in which the liberal certainties of the past 30 years, many of them a response to previous disturbances such as the Brixton riots of 1981, have been tested to destruction. The Prime Minister has been presented with an opportunity to reassert the standards of behaviour and values to which the majority subscribe and are entitled to see upheld. He must seize it.